Monitoring system and camera

ABSTRACT

A monitoring system is provided and includes a camera attached to a train car that takes an image of the vicinity of a door of the car, where a monitor displays a camera image taken by the camera and a dirt detection unit executes a dirt detection process for detecting dirt on the front glass of the camera. This configuration thereby allows the dirt detection unit to determine the execution timing for a dirt detection process on the basis of the train information that indicates the operational state of the train to execute the dirt detection process by using the camera image that has been obtained according to the execution timing.

TECHNICAL FIELD

The present invention relates to a monitoring system for monitoring thevicinity of a door of a train by means of a camera image.

BACKGROUND ART

In train systems, a train driver or a trainman (hereinafter, these aresimply referred to as “trainman”) checks passengers who move along aplatform by means of an image in order to control the opening andclosing of doors after confirming the safety of the passengers. Theimage of the passengers is taken by a camera that is installed on themain body of a car of the train or along the platform so as to bedisplayed on a monitor in the cabin of the train or on a monitor alongthe platform. The difference in the location where the camera has beeninstalled is mainly caused by the difference of whether the operation ofthe train and the infrastructure are managed by the same company ordifferent companies.

In the following, a monitoring system for displaying an image of acamera that is installed on the main body of a car of a train on amonitor in the cabin is described. For example, Patent Literature 1discloses a system where a camera is arranged adjacent to each door ofthe cars.

PRIOR ART LITERATURE Patent Literature

-   Patent Literature 1: WO2015/135736A1

SUMMARY OF THE INVENTION Problem to be Solved

In the above-described system, it is important to take a camera imagehaving high visibility in order for a trainman to control the openingand closing of the doors safely and efficiently. While the operation ofthe train continues, however, the camera image could be hazy as comparedto the time when the state is normal if dirt, such as dust, adheres tothe front glass of the camera. That is to say, it has been confirmedthat the contrast of the camera image decreases during the operation ofthe train, which lowers the visibility. In many cases, the visibility ofthe camera image that has been lowered can be recovered by cleaning thefront glass of the camera. However, many cameras are attached to thetrain, and therefore, the burden of maintenance, including the cleaningoperation, increases. Thus, a scheme for making the cleaning of thefront glass of the cameras efficient has been required.

The present invention has been made in view of the above-describedconventional situation, and an object thereof is to make it possible toefficiently detect dirt on the front glass of the cameras.

Solution to Problems

In order to achieve the above-described object, the present inventionprovides the following configuration of a monitoring system.

That is to say, the monitoring system according to the present inventionis provided with: a camera that is attached to the outside of a car of atrain and that can take an image of the vicinity of a door of the car; amonitor that displays a camera image taken by the camera; and a dirtdetection unit that executes a detection process on dirt on the frontglass of the camera by using a camera image, wherein the dirt detectionunit determines the execution timing for the detection process on thebasis of train information that indicates the operational state of thetrain, and thus executes the detection process by using the camera imagethat has been gained in accordance with the execution timing.

Here, the train information may include information on the speed of thetrain and information on the opening and closing of the doors, and thedirt detection unit may determine the timing when the speed of the trainis a predetermined value or less in the state where the doors are closedas the execution timing.

In addition, the dirt detection unit may execute a detection process ona region of a car body part in a camera image.

Furthermore, the dirt detection unit may add dirt detection informationto the metadata of a camera image in the case where dirt is detected onthe front glass.

Moreover, the dirt detection unit may determine the execution timing forthe detection process under the condition where the time is in a presettime band or the train is in a preset location.

In addition, the dirt detection unit may detect dirt on the front glassby comparing the peak value of the edge components that have beendetected from the camera image with a threshold value. In this case, thethreshold value may be changed in accordance with the time band or thelocation of the train when the detection process is executed.

Furthermore, the dirt detection unit may be built into the camera or maybe provided in another device that can acquire a camera image.

Advantageous Effects of the Invention

The present invention makes it possible to efficiently detect dirt onthe front glass of a camera.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram showing an example of the configuration ofthe monitoring system according to one embodiment of the presentinvention;

FIG. 2 is a diagram showing an example of a camera image in themonitoring system in FIG. 1 ;

FIG. 3 is a diagram showing an example of the configuration of a camerahaving a built-in dirt detection function; and

FIG. 4 is a flow chart showing an example of the dirt detection process.

DESCRIPTION OF EMBODIMENTS

One embodiment of the present invention is described below in referenceto the drawings.

FIG. 1 is a schematic diagram showing an example of the configuration ofthe train equipment type monitoring system according to one embodimentof the present invention. FIG. 1 shows a train formed of four cars wherethe first car 10-1, the second car 10-2, the third car 10-3, and thefourth car 10-4 are connected.

One switching hub 11 is arranged on each car 10-1 through 10-4, andthese switching hubs are cascade connected so as to construct a networkwithin the train. In addition, a camera 13 is attached to the outer sideof each car 10-1 through 10-4 so as to be directed toward the door 12 ofthe car so that an image that shows how passengers get on or off of thetrain can be taken. That is to say, the configuration allows the camera13 to take an image of the vicinity of the door.

A monitor 14 for displaying the camera image that has been taken by thecamera 13 on each car is installed in the trainman's compartment in thefirst car 10-1 and the fourth car 10-4. The trainman can confirm thestate of the passengers in the vicinity of the doors of each car bymeans of the image on the monitor 14. In addition, a control device 16for collectively controlling the present system and a recording device15 for recording camera images are installed in the first car 10-1.

The main feature of the present system is that the camera 13 has abuilt-in function for detecting dirt on the front glass of the camera13. That is to say, the camera 13 executes a dirt detection process fordetecting dirt on the front glass by using the camera image that hasbeen taken by the camera 13 itself. Here, the camera 13 determines theexecution timing for the dirt detection process on the basis of thetrain information that indicates the operational state of the train, andexecutes a dirt detection process by using the camera image that hasbeen gained in accordance with the execution timing.

The camera 13 in the present example is provided with hardware resourcessuch as a memory and a processor so as to be configured in such a mannerthat the below-described process is carried out by reading out theprogram that has been stored in a data storage device, such as a harddisc or a flash memory, onto the main memory and running the program bymeans of the processor. Here, the configuration is not limited to theone where the function of the camera 13 is implemented by means of suchsoftware, but may be one where the function is implemented by dedicatedhardware.

In the following, the dirt detection process that is executed by thecamera 13 is described in reference to FIGS. 2 through 4 .

FIG. 2 shows an example of a camera image that has been taken by thecamera 13. As shown in this figure, the camera image 21 that is used inthe present system is composed in such a manner where part of the carbody 22 of the train (concretely, the vicinity of a door of the car body22) is always shown in a region on one end in the lateral direction. Inaddition, the remaining part of the camera image 21 shows differentviews depending on the location where the train is running such as theoutside scenery or a platform of a station. FIG. 2 is composed in such amanner where part of the car body 22 is shown on the right side of thecamera image 21; however, in some cases, part of the car body 22 appearson the left side depending on the location in which the camera 13 isinstalled. In the present system, the determination region 23 thatbecomes the target of a dirt detection process is set so as to includethe region where the car body 22 always appears.

FIG. 3 shows an example of the configuration of the camera 13 that isused in the present system. The camera 13 has a sensor unit 31, an imageprocessing unit 32, a dirt detection unit 33, an additional imageprocessing unit 34, and an image output unit 35.

The sensor unit 31 is a so-called image pickup device, and converts anoptical image that has entered through the front glass and a lens intoan image signal (electrical signal). The image processing unit 32carries out image processes until the image signal that is outputtedfrom the sensor unit 31 is converted to the final image quality, whichis then outputted to the dirt detection unit 33 and the image outputunit 35.

In addition to the image signal that is outputted from the imageprocessing unit 32, train information from the train car side isinputted into the dirt detection unit 33. This train information atleast includes information on the speed of the train and information onthe opening and closing of the doors. The dirt detection unit 33determines whether or not the speed of the train is a predeterminedvalue or less in the state where the doors are closed on the basis ofthis train information. In addition, the timing when the speed of thetrain is a predetermined value or less in the state where the doors areclosed is determined as the execution timing for the dirt detectionprocess.

The dirt detection unit 33 uses the image signal that has been gained inaccordance with the execution timing for the dirt detection process inorder to execute the dirt detection process. Concretely, an edgedetection filter is applied to the image signal so as to detect edgecomponents from within the above-described determination region 23, andthen, the peak value of the edge components is compared with apredetermined threshold value (fixed value in the present example). Inthe case where the peak value of the edge components is the thresholdvalue or less resulting from the comparison, the image is in a statewhere the contrast has been lowered, and thus, it is determined that thefront glass has dirt thereon. Then, alarm information to the effect thatdirt has been detected on the front glass is outputted, and at the sametime, an additional image process is instructed to the additional imageprocessing unit 34.

The additional image processing unit 34 follows the instructions fromthe dirt detection unit 33 so as to carry out an additional imageprocess on the image signal that is outputted from the image processingunit 32. The additional image process may be any process that canimprove the visibility of the image, and a haze removal process forstretching the contrast of the image can be cited as an example. Theimage signal after the additional image process by means of theadditional image processing unit 34 is outputted to the image outputtingunit 35.

The image output unit 35 usually outputs the image signal from the imageprocessing unit 32 to the outside of the camera. In the case where thedirt detection unit 33 has detected dirt on the front glass, the imagesignal from the additional image processing unit 34 is outputted to theoutside of the camera in place of the image signal from the imageprocessing unit 32. Here, the image output unit 35 may output both theimage signal from the image processing unit 32 and the image signal fromthe additional image processing unit 34.

The image signal (camera image) that has been outputted from the imageoutput unit 35 is transmitted to the monitor 14 through the networkwithin the train and displayed on the monitor 14. In addition, the alarminformation that has been outputted from the dirt detection unit 33 istransmitted to the monitor 14 through the network within the train anddisplayed on the monitor 14 together with the camera image. Accordingly,it becomes possible for the trainman who has seen the display on themonitor 14 not only to be able to confirm the state of the passengers,but also to grasp the condition of the front glass of the camera 13 inthe case where dirt is present. A great number of cameras 13 is attachedto the train, and therefore, it is preferable for the display to be insuch a manner that it can be understood which camera 13 has dirt on thefront glass.

FIG. 4 shows the flow chart of the dirt detection process.

The image signal from the image processing unit 32 is inputted into thedirt detection unit 33 (step S1). The dirt detection unit 33 determineswhether or not the speed of the train is a predetermined value or lessin the state where the doors are closed on the basis of the traininformation that is separately inputted from the train car side (stepS2). In the case where this condition is not present (“No” in step S2),the image signal from the image processing unit 32 is outputted from theimage outputting unit 35 (step S6). Meanwhile, in the case where it hasbeen determined that this condition is present (“Yes” in step S2), thedirt detection unit 33 applies an edge detection filter to the imagesignal from the image processing unit 32 in order to detect the edgecomponents from within the determination region 23 (step S3).

After that, the dirt detection unit 33 determines whether or not thepeak value of the edge components within the determination region 23 isa threshold value or less (step S4). In the case where it has beendetermined that this condition is not present (“No” in step S4), theimage signal from the image processing unit 32 is outputted from theimage output unit 35 (step S6). Meanwhile, in the case where it has beendetermined that this condition is present (“Yes” in step S4), alarminformation is outputted from the dirt detection unit 33, and at thesame time, an additional image process (haze removal process, forexample) is carried out by the additional image processing unit 34 (stepS5). After that, the image signal after the image processing by means ofthe additional image processing unit 34 is outputted from the imageoutput unit 35 (step S6).

As described above, the monitoring system in the present example isprovided with: a camera 13 that is attached to the outside of a car of atrain and that can take an image of the vicinity of a door of the car; amonitor 14 that can display a camera image taken by the camera 13; and adirt detection unit 33 that can execute a dirt detection process fordetecting dirt on the front glass of the camera 13. Thus, theconfiguration allows the dirt detection unit 33 to determine theexecution timing for a dirt detection process on the basis of the traininformation that indicates the operational state of the train in orderto execute the dirt detection process by using the camera image that hasbeen obtained according to the execution timing.

In such a configuration, the timing according to which an appropriatecamera image for executing a dirt detection process can be gained can bedetermined by taking the operational state of the train intoconsideration, and therefore, dirt on the front glass of a camera can beefficiently detected.

In addition, the configuration in the present example allows the dirtdetection unit 33 to determine the timing according to which the speedof the train is a predetermined value or less in the condition where thedoors are closed as the execution timing for the dirt detection process.As a result, the dirt detection process can be executed by using acamera image that shows a state where the train has entered the platformarea, and no passengers are shown around the periphery of the door, andtherefore, the dirt detection can be implemented with high precision.

In addition, the dirt detection unit 33 in the present example isconfigured in such a manner that the region of the car body part in thecamera image is designated as the determination region 23, and the dirtdetection process is executed on the determination region 23. As aresult, only the analysis of the condition in a region where imagealteration is small is necessary, and wasteful processes on otherregions can be omitted, and therefore, the process burden of the dirtdetection process can be reduced.

According to the above description, alarm information is merelyoutputted, and only an additional image process (haze removal process,for example) is carried out in the case where dirt is detected on thefront glass of a camera; however, another process may be carried out inplace of or in addition to these processes.

For example, in the case where dirt is detected on the front glass, thedirt detection unit 33 may add dirt detection information to themetadata of the camera image. The metadata is data that relates to traininformation accompanying the camera image, and is stored in a dataregion that does not affect the image display of the camera image or isstored as a different piece of data that can be associated with thecamera image. As examples of the dirt detection information, a dirtdetection flag that indicates to the effect that dirt has been detected,the dirt detection time, the dirt detection location and the like can becited. The dirt detection location can be acquired by utilizing a GPS(global positioning system), for example. When and where the front glassof a camera has gotten dirt can be understood after the event by addingdirt detection information as described above to the metadata of thecamera image. In addition, the dirt detection information can be used asthe material to be examined when a measure for dirt prevention is to becarried out, for example.

According to the above description, the execution timing for the dirtdetection process is determined on the basis of the information on thespeed of the train and information on the opening and closing of thedoors; however, other pieces of information may be additionally takeninto consideration. For example, the execution timing for the dirtdetection process may be determined under the condition where the timeis in the preset time band. As a result, it becomes unnecessary toexecute the dirt detection process in a time band when it is difficultfor a clear image to be gained (in the evening, for example), andtherefore, it becomes possible to suppress the output of wasteful alarminformation due to an error in detecting the dirt. As another example,the execution timing for the dirt detection process may be determinedunder the condition where the train is in a preset location. As aresult, it becomes unnecessary to execute the dirt detection process ina station where it is difficult to clean the front glass of the cameras(a station where there are no sanitation workers or a station where thetime during which a train stops is short, for example), and therefore,it becomes possible to reduce the work burden of cleaning the frontglass of the cameras.

According to the above description, the peak value of the edgecomponents that have been detected from the camera image is compared toa fixed threshold value; however, the threshold value may be variable.As an example, the threshold value may be changed in accordance with thetime band when the detection process is executed. As a result, the dirtdetection process can be executed by taking into consideration thedifference in the contrast of the camera image depending on the timeband when the image is taken, and therefore, dirt on the front glass ofa camera can be detected more precisely. As another example, thethreshold value may be changed in accordance with the location of thetrain when the detection process is executed. As a result, the dirtdetection process can be executed by taking into consideration thedifference in the contrast of the camera image between a station wherethe platforms have a roof and a station where there are no roofs, andtherefore, dirt on the front glass of a camera can be detected moreprecisely.

According to the above description, the dirt detection unit 33 that isbuilt into a camera 13 executes a dirt detection process; however,another device (control device 16, for example) that is connected to thenetwork within the train may execute the dirt detection process. That isto say, the dirt detection process can be executed by an arbitrarydevice that can acquire a camera image.

Though the present invention is described in detail in the above, thepresent invention is not limited to the above-described configurations,but needless to say may be implemented with configurations other thanthe above. For example, it is possible for the present invention to beapplied to various types of trains that include a monorail and astreetcar in addition to a train that runs on a railway.

It is also possible to provide the present invention as a method thatincludes a technical procedure relating to the above-describedprocesses, a program for allowing a processor to execute theabove-described processes, a storage medium for storing such a programin a computer readable manner, and the like.

Here, the scope of the present invention is not limited to theillustrative embodiments that are shown and described herein andincludes all the embodiments that provide equal effects targeted by thepresent invention. Furthermore, the scope of the present invention canbe defined by all the desired combinations of the specific features fromamong all the features that have been disclosed herein.

INDUSTRIAL APPLICABILITY

It is possible to apply the present invention to a monitoring system formonitoring the vicinity of a door of a train by means of a camera image.

REFERENCE SIGNS LIST

-   -   10-1, 10-2, 10-3, 10-4: Car    -   11: Switching hub    -   12: Door    -   13: Camera    -   14: Monitor    -   15: Image recording device    -   16: Control device    -   31: Sensor unit    -   32: Image processing unit    -   33: Dirt detection unit    -   34: additional image processing unit    -   35: Image output unit

1. A train equipment type monitoring system, comprising: a camera thatis attached to the outside of a car of a train and that takes an imageof the vicinity of a door of the car; a monitor that displays a cameraimage taken by the camera; and a dirt detection unit that executes adetection process on dirt on a front glass of the camera by using thecamera image, wherein the dirt detection unit determines an executiontiming for the detection process on the basis of train information thatindicates an operational state of the train, and thus executes thedetection process by using the camera image that has been gained inaccordance with the execution timing.
 2. The monitoring system accordingto claim 1, wherein the train information includes information on thespeed of the train and information on the opening and closing of thedoors, and the dirt detection unit determines the timing when the speedof the train is a predetermined value or less in the state where thedoors are closed as the execution timing.
 3. The monitoring systemaccording to claim 1, wherein the dirt detection unit executes thedetection process on a region of a car body part in the camera image. 4.The monitoring system according to any of claim 1, wherein the dirtdetection unit adds dirt detection information to metadata of the cameraimage in the case where dirt is detected on the front glass.
 5. Themonitoring system according to claim 1, wherein the dirt detection unitdetermines the execution timing under the condition where the time is ina preset time band or the train is in a preset location.
 6. Themonitoring system according to claim 1, wherein the dirt detection unitdetects dirt on the front glass by comparing the peak value of the edgecomponents that have been detected from the camera image with athreshold value, and the threshold value is changed in accordance withthe time band or the location of the train when the detection process isexecuted.
 7. The monitoring system according to claim 1, wherein thedirt detection unit is built into the camera.
 8. A camera that isattached to the outside of a car of a train and that takes an image ofthe vicinity of a door of the car, the camera comprising: a built-indirt detection unit that executes a detection process on dirt on a frontglass of the camera by using a camera image, wherein the dirt detectionunit determines an execution timing for the detection process on thebasis of train information that indicates an operational state of thetrain, executes the detection process by using the camera image that hasbeen gained in accordance with the execution timing, and adds dirtdetection information to metadata of the camera image in the case wheredirt is detected on the front glass.